import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.JOptionPane;
import javax.swing.SwingUtilities;
import javax.swing.filechooser.*;

import javax.swing.text.*;
import java.io.*;

/**
* Class <code>FileChooser</code> is used to demo opening and closing file.
*
* @author  Mely
* @version 1.73, 03/30/06
* @see     javax.swing.filechooser.JFileChooser;
* @since   JDK1.0
*/
public class FileChooser extends JFrame {

    private JTextArea log;
    private static final JFileChooser fc = new JFileChooser();
    private static final String txt = ".txt";

    static {
        //Add a custom file filter and disable the default
        //(Accept All) file filter.
        //fc.addChoosableFileFilter(new TxtFilter());
        fc.setAcceptAllFileFilterUsed(false);
    }

    private String newline = System.getProperty("line.separator");

    public FileChooser() {
        super("FileChooserDemo");

        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setSize(400, 200);


        JButton openButton = new JButton("Open", new ImageIcon("images/open.gif")); //Create the open button and add image
        openButton.addActionListener(new OpenListener()); //Adds action listener to the open button

        JButton saveButton = new JButton("Save", new ImageIcon("images/save.gif")); //Create the save button and add image
        saveButton.addActionListener(new SaveListener()); //Adds action listener to the save button
        Dimension btnSize = new Dimension(100, 30);
        openButton.setPreferredSize(btnSize);
        saveButton.setPreferredSize(btnSize);
        JPanel buttonPanel = new JPanel(); //Create a panel
        buttonPanel.add(openButton); //Add the open button to the panel
        buttonPanel.add(saveButton); //Add the save button to the panel

        log = new JTextArea(5,20); //Create the text area
        log.setMargin(new Insets(5,5,5,5)); //Set the margins
        JScrollPane logScrollPane = new JScrollPane(log);

        Container contentPane = getContentPane();
        contentPane.add(buttonPanel, BorderLayout.PAGE_START); //Add the buttons to the panel
        contentPane.add(logScrollPane, BorderLayout.CENTER); //Add the text area to the panel
    } //end of constructor


    /**
     * Find the hosting frame, for the file-chooser dialog.
     *
     * @return  a frame of this parent.
     */
    protected Frame getFrame() {
        for (Container p = getParent(); p != null; p = p.getParent())
            if (p instanceof Frame)
                return (Frame) p;
        return null;
    }


    private class OpenListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            int returnVal = fc.showOpenDialog(FileChooser.this);

            if (returnVal == JFileChooser.APPROVE_OPTION) {
                File file = fc.getSelectedFile();

                log.append("Opening: " + file.getName() + "." + newline); //Display "Opening" and the retrieved file name in the text area
            } else
                log.append("Open command cancelled by user." + newline); //Display this command in the text area
        }
    } //end of class OpenListener

    private class SaveListener implements ActionListener {

        public void actionPerformed(ActionEvent e) {
            int returnVal = fc.showSaveDialog(FileChooser.this);

            if (returnVal == JFileChooser.APPROVE_OPTION) {
                File file = fc.getSelectedFile();

                if (file.exists()) {
                    //default icon, custom title
                    int n = JOptionPane.showConfirmDialog(
                        getFrame(),
                        "File already exists. Would you like to override it?",
                        "Override File?",
                        JOptionPane.YES_NO_OPTION);

                    if (n == JOptionPane.NO_OPTION) {
                        //log.append("Save command cancelled by user. User do not wish to override it." + newline); //Display this command in the text area
                        JOptionPane.showMessageDialog(getFrame(),"Save command cancelled by user. User do not wish to override it.");
                        return;
                    }
                } //end of if (file.exists())
                boolean isAcceptedExtension = fc.accept(file);

                if (!isAcceptedExtension) {
                    //Custom button text
                    Object[] options = {"Yes, please",
                                        "No, thanks",
                                        "Don't do anything"};
                    int n = JOptionPane.showOptionDialog(getFrame(),
                        "The file name does not have '.txt' extension.\n\n"
                        + "Would you like the program to append '.txt' to the filename on behalf of you?\n\n"
                        + String.format("<html><body>Changing filename from <span style='font-family: monospace'><font color=#ff0000>'%s'</font> to <font color=#ff0000>'%s.txt'</font></span></body></html>\n", file.getPath(), file.getPath()),
                        "A Confirmation Question",
                        JOptionPane.YES_NO_CANCEL_OPTION,
                        JOptionPane.QUESTION_MESSAGE,
                        null,
                        options,
                        options[2]);


                    if (n == JOptionPane.YES_OPTION) {
                        file = makeTxt(file);
                        isAcceptedExtension = true;
                    }
                } //end of if (!isAcceptedExtension)

                if (isAcceptedExtension) {
                    Thread saver = new FileSaver(file, log.getDocument());
                    saver.start();

                    //log.append("Saving: " + file.getName() + "." + newline); //Display "Saving" and the retrieved file name in the text area
                    JOptionPane.showMessageDialog(getFrame(),"Saving : " + file.getName() + ".");
                } else
                    //log.append("Saving Failed: " + file.getName() + " does not END with (.txt)." + newline); //Display "Saving" and the retrieved file name in the text area
                    JOptionPane.showMessageDialog(getFrame(),"Saving Failed....");
            } else
                log.append("Save command cancelled by user." + newline); //Display this command in the text area
        }
    } // end of class SaveListener

    public static void main(String s[]) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                new FileChooser().setVisible(true);//Set frame to visible
            }
        });
    }

    /**
     * Changed the extension to .txt if it has not done.
     *
     * @param f file to be changed.
     * @return File that has been changed.
     */
    private File makeTxt(File f) {
        return f.getName().endsWith(txt) ? f : new File(f.getPath().concat(txt));
    }


    /**
     * Thread to save a document to file
     */
    private class FileSaver extends Thread {
        private Document doc;
        private File f;


        FileSaver(File f, Document doc) {
            setPriority(4);
            this.f = f;
            this.doc = doc;
        }

        public void run() {
            JComponent status = new JPanel();
            JFrame frame = new JFrame("Saving...");
            try {

                // initialize the statusbar
                status.removeAll();
                JProgressBar progress = new JProgressBar();
                progress.setMinimum(0);
                progress.setMaximum((int) doc.getLength());
                status.add(progress);
                status.revalidate();

                Container c = frame.getContentPane();
                c.setLayout(new BoxLayout(c, BoxLayout.PAGE_AXIS));
                c.add(status);
                c.add(new JLabel(String.format("Saving file '%s' in '%s'", f.getName(), f.getPath())));
                c.add(new JLabel("Please wait..."));

                frame.pack();
                frame.setVisible(true);
                halt(2000);

                // start writing
                Writer out = new FileWriter(f);
                Segment text = new Segment();
                text.setPartialReturn(true);
                int charsLeft = doc.getLength();
                int offset = 0;
                while (charsLeft > 0) {
                    doc.getText(offset, Math.min(4096, charsLeft), text);
                    out.write(text.array, text.offset, text.count);
                    charsLeft -= text.count;
                    offset += text.count;
                    progress.setValue(offset);
                    halt(10);
                }
                out.flush();
                out.close();
            } catch (IOException e) {
                final String msg = e.getMessage();
                SwingUtilities.invokeLater(new Runnable() {
                    public void run() {
                        JOptionPane.showMessageDialog(getFrame(),
                                "Could not save file: " + msg,
                                "Error saving file",
                                JOptionPane.ERROR_MESSAGE);
                    }
                });
            } catch (BadLocationException e) {
                System.err.println(e.getMessage());
            }
            // we are done... get rid of progressbar
            status.removeAll();
            status.revalidate();
            halt(2000);
            frame.setVisible(false);
        }
    }  // end of class FileSaver

    /**
     * Waiting for the human's eye to grasp the information.
     */
    private static final void halt(int ms) {
        try {
            Thread.sleep(ms);
        } catch (InterruptedException exception) {
            System.err.println("Thread had been interrupted..");
        }
    }
}  // end of FileChooser